Field of the Invention
The present invention relates to an image sensor, an image capturing apparatus, a focus detection apparatus, an image processing apparatus, and a method of controlling the same.
Description of the Related Art
As a focus detection method of an image capturing apparatus, an image capturing surface phase difference method in which a phase difference method focus detection is performed in accordance with a focus detection pixel formed on an image sensor is known.
Japanese Patent Laid-Open No. S58-024105 discloses an image capturing apparatus that uses a microlens and an image sensor in which a plurality of divided photoelectric conversion regions are formed for one pixel. Each divided photoelectric conversion region receives a light beam in each of different regions of an exit pupil via the microlens, realizing pupil division. The image capturing apparatus can perform the phase difference method focus detection by obtaining an image shift amount from signals (parallax signals) for which there is a parallax obtained by the pupil division. In addition, Japanese Patent Laid-Open No. 2001-083407 discloses a technique of generating an image signal by adding parallax signals received by divided photoelectric conversion regions.
However, to obtain parallax signals for more viewpoints from the image sensor, it is necessary to increase the number of divisions of the photoelectric conversion region for one pixel, but there is the problem that if the total number of signal reads for the photoelectric conversion region increases, it leads to an increase of a signal amount and power consumption.